As an example, PHP has a direct module interface called SAPI for different web servers.[2] For PHP 5 and Apache 2.0 on Windows, it is in form of a DLL file called php5apache2.dll,[3] which is a module that—​among other functions—​provides an interface between PHP and the web server, implemented in a form that the server understands. This form is what is known as a SAPI.